what is this part and what do I do to stop the oil leak?

[Craig]

Guys,

I have a small oil leak coming from the round part shown in photo on my D1-30. The "Button" is loose but there does not appear to be any way to tighten it. the central part moves around. I could not identify it on the parts diagram on euromarineparts.

It is located near where the raw water pump enters the main engine housing.

Craig
"Shirley Valentine"
Gold Coast
Australia

[Yngmar]

Not familiar with that engine, but the part looks like a freeze plug. It's labeled "Expansion plug" here: https://www.marinepartseurope.com/en/volvo-penta-explodedview-7746500-23-35201.aspx

Looks like the thing is fitted with a bolt and gasket coming from the inside of the assembly, so that'll be quite annoying to tighten - the assembly will have to come off the engine. Definitely get the gasket(s) before starting the job, as it'll likely need replacing.

[Craig]

Thanks Yngmar,

Looks like a big job for a small leak. I can't see what would have made it fail, given I live in Australia and temperature does not get to freezing.

Craig
"Shirley Valentine"
Gold Coast
Australia